Field of the Invention
The present invention relates to a holding device, a transport device, a lithographic apparatus, and an article manufacturing method.
Description of the Related Art
There is a transport device which transports a substrate to a lithographic apparatus for manufacturing semiconductor devices and the like from the outside of the apparatus. The transport device includes, for example, a holding portion which holds a substrate and a drive portion which drives the holding portion. The drive portion moves the holding portion on which a substrate is held to the inside of the device (a substrate stage and the like) after a placement of the substrate on the holding portion is detected (a load presence detection). The substrate is held by vacuum adsorption which exhausts gas between the holding portion and the substrate using, for example, a mechanism which includes an adsorption hole provided in the holding portion, an exhaust flow path connected to the adsorption hole, and an exhaust unit connected to the exhaust flow path (Japanese Patent Laid-Open No. 2000-195926).
The load presence detection is performed on the basis of changes in pressure in the exhaust flow path, which is caused by, for example, the adsorption hole being closed by the substrate, and there can be erroneous load presence detection when the adsorption hole is insufficiently closed due to a shape (a concavity and convexity, warpage, a hole, and the like) of a substrate in the technology disclosed in Japanese Patent Laid-Open No. 2000-195926. This is because an amount of change in an adsorption pressure force value before and after adsorption can be small if there is a hole in an adsorption surface of the substrate.